Peanut seed tegument is affected by liming and drying method

Calcium plays a fundamental role in cell division and growth, and is an imp ortant constituent of the cell wall. An increase in Ca concentration in the tegument of peanut (Arachis hypogea L.) seeds in response to lime applicat ion can affect its structure. The tegument structure can also be affected b y the drying method of the seeds. The effects of lime application and dryin g methods as affecting the peanut seed tegument structure were studied in s eeds from a field experiment conducted in Sao Manuel, Sao Paulo, Brazil. Pe anut (cv. Botutatu, Valencia Type) was grown in presence or absence of 2.1 Mg ha(-1) of lime and dried in an oven, in shade and in the field. The tegu ment anatomical features were described and its structure was analysed. Pec tic substances, lipidic reserves and starch accumulation were studied. The peanut tegument exhibited well differentiated exotesta, mesotesta and endot esta rich in pectates and covered by a cuticle. Tannin was not observed but there was lipid accumulation in mature teguments. Lignin was observed in t he vascular bundles. Lime increased the tegument thickness and decreased th e central cavity mainly in the exotesta cells when the period of seed dryin g was shortened. The effect of drying method upon the tegument was more not iceable in seeds grown without lime. It can be inferred that liming increas ed the resistance of the tegument.